He is equally mum about his four-month marriage to actress Jennifer Esposito. "It was an experience," he simply says.

Cooper may get hearts racing this summer with his taut and toned bod in The A-Team (out June 11), but he tells Details: "I never lived the life of 'Oh, you're so good-looking.' People thought I was a girl when I was little, because I looked like a girl — maybe because my mother would keep my hair really long in a bowl cut. I was in a coffee shop once and the waitress was like, 'What do you want, Miss?' I was 10 or 11 — the worst age to have that happen. I had a jean jacket on and a Metallica pin. I thought I was really cool."

As for his bulging biceps and concrete pecs in The A-Team, "I had to literally transform my body," he says.

In addition to cutting out sugar, salt, and flour, he worked out two hours-a-day with a trainer.

"As the movie progressed, I got in increasingly better shape," he tells Details. "There's this one fight scene with Liam Neeson toward the end, where it's, like, the apex of the work ... I swear to God, it looked like my head was digitally superimposed onto someone else's body. I was like, 'This cannot be me—that's the way I look?' ... 'Cause as a kid I only fantasized about looking that way. Remember Soloflex commercials? That was huge when I was a kid. It was like, 'I wanna be the Soloflex guy. Mom, can we get the Soloflex?'"